(a) Field of the Invention
The present invention relates to a lens assembly for monitor with infrared (IR) and focus adjustment.
(b) Description of the Prior Art
FIGS. 1 and 2 show a conventional monitor with lens assembly. The monitor A1 can be combined with an IR device for use at night. If it is needed, the IR device can be mounted to the monitor A1 to provide night photography. The disadvantages of this conventional monitor A1 are that
(1) The IR device is a separate component and stands alone and therefore, it has to be bought and installed separately. This will increase the cost of installation.
(2) In view of the main lens used in the monitor A1 where different f-stop numbers are used, for instance, f/4.0, f/6.0, f/8.0. Thus, the IR device has to be appropriately selected in order to match with the main lens of the monitor A1. Otherwise, the quality of photograph is affected.
(3) In operating an IR device, the device has to adjusted and installed based on the similar orientation of the lens A2 of the monitor. The quality of the photography at night is similarly affected depending on the orientation adjustment. If the device is not appropriately adjusted to within a certain range. The night photography function of the IR device is lost.
FIG. 2 is a conventional lens device A2 of a monitor, comprising a lens seat A21, a rim seat A22 and a locking seat A23. The lens seat A21 includes main lens A211, and the main lens A211 is combined together with the lens seat A21 as an inseparable unit. The lens seat A21 has a screw body A212 mounted at the inner screw hole A221 of the rim seat A22 together with a spring A24 to enhance their mounting. The locking seat A23 and the rim seat A22 and screwed together so as to assist the entire lens device A2 to be mounted onto the monitor A1. The lens device A2 of the monitor has the function of focus adjustment, and the method of adjustment is by rotating the lens seat A21 to cause a displacement within the rim seat A22 (i.e., rim seat A22 is stationery). The mechanism of the displacement is totally restricted by the range of the spring force of the spring A24. Thus, the gap of focus adjustment is relatively small and the mechanism thereof is weak. Other than the problem of accommodation the main lens A211 of the conventional monitors cannot be partially replaced, for instance, to select f/4.0, f/6.0, f/8.0. Thus, the option of replacement of lens is restricted.
Accordingly, it is an object of the present invention to provide a lens assembly for monitor with infrared and focus adjustment, wherein the above-mentioned drawbacks are mitigated.
Yet another object of the present invention to provide a lens assembly for monitor with infrared and focus adjustment, wherein the main lens can be replaced in part so that the monitor is provided with the replacement options of lens.
An aspect of the present invention is to provide a lens assembly for monitor with infrared and focus adjustment comprising (a) a blocking rim, (b) a front cover, (c) an IR device, (d) a main lens, (e) a main lens mounting rim, (f) a tension spring, (g) an adjustment rim, (h) a mount-connection plate; and (i) an adjustment rim mounting plate; wherein the blocking rim is mounted at the internal screw threads of the inner edge of the adjustment rim, forming into a blocking edge of the external edge of the bottom of the front cover; the front cover is provided with a plurality of rim-like, conic shape through hole at the front face thereof, the center of the front cover is a slanting face and a throng hole with edged side is provided at the center section of the slanting face, the main lens is engaged within the through hole; the front cover is screwed to the adjustment rim by means of a screw seat within the front cover, and the symmetrical peg hole slot located on the screw seat face is inserted by a peg protrusion to secure with the mount-connection plate to form a tight engagement; the IR device has a rim-like structure as that of the circumferential face of the front cover and includes a plurality of rim-like IR emitters and a photosensor, the entire IR device is hidden within the front cover, and the plurality of IR emitter and the photosensor are mounted correspondingly into the conic hole, and a lead wire is inserted through the lead hole provided on the front cover and is then conductively connected with the IR device; the main lens is located at the through hole of the center of the slanting face of the front cover and the inner screw slot seat at the front cover center located at the main lens mounting rim mounts the main lens at the front edge thereof; the main lens mounting rim is screwed to the center inner screw slot seat of the front cover by the screw threads at the external edge thereof so as to engage the main lens; the tension spring is located at the space formed between the front cover and the middle slot of the mount-connection plate, and the tensional force allows a comparatively large width and tight screw mounting; the adjustment rim is screwed to the screw seat of the front cover by the middle slot screw seat of the interior thereof and the external edge of the middle slot screw seat is provided with a screw hole for the locking with the adjustment rim mounting plate so as to lock the adjustment rim mounting plate within the bottom slot; the mount-connection plate is located within the bottom external edge of the adjustment rim middle slot screw seat, and is screwed to the monitor by means of the screwed end thereof and the middle slot can hold the tension spring, and the peg protrusion is engaged at the peg hole slot of the front cover and is locked with the adjustment rim mounting plate of the adjustment rim at the top section thereof, forming a pivotally rotatable, relative structure; and the adjustment rim mounting plate is mounted within the bottom slot of the adjustment rim by a locking screw, and the adjustment rim is adjusted to form a pivotally rotatable, relative structure with the mount-connection plate.
Other objects, advantages and features of the present invention will become apparent from the following description taken together with the accompanying drawings.